1. Field of the Invention
The invention relates to image sensing device fabrication, and in particularly to methods for forming a light-transmitting region of an image sensing device.
2. Description of the Related Art
Recently, image sensing devices such as solid state image sensing devices are being used in a very wide range of optoelectronic devices including, for example, digital cameras, cellular phones, and toys. Conventional image sensing devices include image sensors such as charge coupled device (CCD) image sensors and complementary metal oxide semiconductor (CMOS) image sensors.
In the art of solid state imaging devices, microlenses are typically provided to improve image sensitivity. In addition, a diaphragm is typically provided within the solid state imaging device as a light path filter of the microlenses, to therby regulate the amount of light that passes through the microlenses and toward the image sensors therein.
The diaphragm is typically defined over a top surface of the microlenses by forming a patterned light-blocking layer by photolithgraphy techniques over the top surface of the microlenses. Since the microlenses are typically provided with a curved surface, photolithgraphy techniques performed to the portion of the light-blocking layer formed over the curved surface of the microlenses may result in uneven exposure uniformalty and repeatablity during patterning thereof. Moreover, the use of photolithgraphy techniques also have disadvantages of increasing fabrication costs and time.